Fire Fighting
Sprinklers A fire sprinkler or sprinkler head is the component of a fire sprinkler system that discharges water when the effects of a fire have been detected, such as when a predetermined temperature has been exceeded. Fire sprinklers are extensively used worldwide, with over 40 million sprinkler heads fitted each year. In buildings protected by properly designed, and maintained fire sprinklers, over 99% of fires were controlled by fire sprinklers alone. Pendant Sprinkler Head Pendant sprinkler heads hang down from the ceiling and spray water in a circle pattern. Concealed Pendant Sprinkler Head Concealed pendant sprinkler heads are recessed in a ceiling and are covered with a decorative cap. The cap will fall away about 20°F prior to activation of the sprinkler. Once the sprinkler reaches its rated activation temperature, the head will drop below the ceiling. The water pattern of concealed sprinkler heads is a circle. Upright Sprinkler Head Upright sprinkler heads project up into a space and have deflectors that spray the water downward. They are generally used in mechanical rooms or other inaccessible areas to provide better coverage between obstructions like beams or ducts. They also provide a circle spray pattern Side Wall Sprinkler Head Side wall sprinkler heads stand out from a wall and have a deflector that sprays water away from the wall in a half-circle spray pattern. A second deflector also sprays water back toward the wall so that the wall is protected. These are used when sprinklers cannot be located in the ceiling. Extinguishers A fire extinguisher, or extinguisher, is an active fire protection device used to extinguish or control small fires, often in emergency situations. It is not intended for use on an out-of-control fire, such as one which has reached the ceiling, endangers the user (i.e., no escape route, smoke, explosion hazard, etc.), or otherwise requires the expertise of a fire department. Typically, a fire extinguisher consists of a hand-held cylindrical pressure vessel containing an agent which can be discharged to extinguish a fire. Types of extinguishing agents #Dry Chemical:This is a powder based agent that extinguishes by separating the four parts of the fire tetrahedron. It prevents the chemical reactions involving heat, fuel, and oxygen and halts the production of fire sustaining "free-radicals", thus extinguishing the fire. #Foams:Applied to fuel fires as either an aspirated (mixed and expanded with air in a branch pipe) or nonaspirated form to form a frothy blanket or seal over the fuel, preventing oxygen reaching it. Unlike powder, foam can be used to progressively extinguish fires without flashback. #Water:Cools burning material. Very effective against fires in furniture, fabrics, etc. (including deep seated fires), but can be safely used only in the absence of electricity. #Wet Chemicals and Water Additives. #Clean Agents and Carbon Dioxide:Agent displaces oxygen (CO2 or inert gases), removes heat from the combustion zone or inhibits chemical chain reaction (Halons). They are labelled clean agents because they do not leave any residue after discharge which is ideal for sensitive electronics and documents. #Class D. #Fire Extinguishing Ball. #Condensed Aerosol Fire Suppresion. #Low-Frequency Sound. Fire Types and Extinguishers to use fire-extinguisher-types.jpg SD_FireClasses_Table2.png